Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 241330
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
330 AM HST FRI OCT 24 2014

.SYNOPSIS...
TRADE WINDS WILL STAY MODERATE THROUGH TODAY...THEN WEAKEN THROUGH
THE WEEKEND AND INTO NEXT WEEK AS HIGH PRESSURE TO OUR NORTH
INITIALLY APPROACHES US...THEN MOVES OFF TO THE EAST. CLOUDS AND
SHOWERS WILL CONTINUE TO FAVOR WINDWARD AND MAUKA AREAS...WITH DRIER
CONDITIONS EXPECTED BY EARLY NEXT WEEK. LEEWARD AREAS MAY SEE LOCAL
LAND AND SEA BREEZES MONDAY AND TUESDAY. TRADE WINDS MAY INCREASE
AGAIN LATE NEXT WEEK AS ANOTHER HIGH BUILDS IN TO OUR NORTH.

&&

.DISCUSSION...
A 1029 MB HIGH NEAR 41N158W...FAR NORTH OF THE MAIN HAWAIIAN
ISLANDS...HAS AN ASSOCIATED RIDGE EXTENDING SOUTHEAST THROUGH
30N153W AND 23N140W. THE PRESSURE GRADIENT BETWEEN THIS RIDGE AND
EQUATORIAL LOW PRESSURE IS SUFFICIENTLY STEEP TO SUPPORT MODERATE
TRADE WINDS ACROSS LOCAL WATERS THIS MORNING. SATELLITE LOOP SHOWS
PATCHES OF BROKEN SHOWERY LOW CLOUDS ARE EMBEDDED WITHIN TRADE FLOW
UPWIND FROM THE ISLANDS...AND THE PATCH NOW ACROSS THE ISLANDS WILL
CONTINUE TO PROVIDE INCREASED CLOUD COVER AND TRADE SHOWERS ACROSS
WINDWARD AND MAUKA AREAS THROUGH MUCH OF TODAY. WE EXPECT MODERATE
TRADES WILL LAST THROUGH TODAY AS THE HIGH MOVES SOUTHEASTWARD ALONG
THE RIDGE...INITIALLY APPROACHING THE ISLANDS. BY SATURDAY
AFTERNOON...MODELS SHOW THE HIGH WILL BE SHOVED EASTWARD BY DEEP
TROUGHING IMPINGING ON IT FROM THE NORTHWEST. THE RIDGE WILL REMAIN
NORTH OF THE ISLANDS THROUGH THE FORECAST PERIOD...KEEPING US WITHIN
TRADE FLOW. HOWEVER...WINDS WILL WEAKEN AS THE PRESSURE GRADIENT
SLACKENS WITH THE DEPARTURE OF THE HIGH TO THE EAST. LEEWARD AREAS
MAY SEE DEVELOPMENT OF LOCAL LAND AND SEA BREEZES BY MONDAY OR
TUESDAY.

MODELS SHOW HIGH PRESSURE MAY BUILD IN TO THE NORTH OF THE ISLANDS
AGAIN LATE NEXT WEEK AS DEEP TROUGHING TO THE NORTHWEST LIFTS OUT.
CONFIDENCE REMAINS LOW THAT FAR OUT GIVEN THE RUN-TO-RUN VARIABILITY
IN GUIDANCE...BUT IF THE GFS SCENARIO PANS OUT WE MAY HAVE A 1035 MB
HIGH 1200 MILES NORTH OF THE ISLANDS DRIVING MODERATE TO LOCALLY
STRONG TRADE WINDS ACROSS THE ALOHA STATE BY HALLOWEEN. GFS ALSO
DEPICTS A FRONT SLOWLY DRIFTING SOUTH TOWARD THE ISLANDS BY NEXT
WEEKEND.

&&

.AVIATION...
TRADE WIND SHOWERS WILL MAINLY AFFECT WINDWARD AND MAUKA SECTIONS
THIS MORNING AND LATER TODAY. THE LOWER CLOUDS AND RAIN WILL BRING
TEMPO MVFR CONDITIONS AS THEY MOVE WEST. FOR THE MOST PART...
LEEWARD AREAS WILL REMAIN VFR.

CURRENTLY...THERE ARE NO AIRMETS IN EFFECT.

&&

.MARINE...
A MINOR NORTHERLY SWELL GENERATED BY LOW PRESSURE OVER THE GULF OF
ALASKA LAST WEEKEND WILL FADE QUICKLY. THIS LOW WEAKENED BUT HAS
BEEN REPLACED BY A STRONGER LOW. MOST OF THE SWELL ENERGY WITH THIS
SECOND LOW WILL BE AIMED TO THE EAST OF THE ISLANDS...BUT WE SHOULD
CATCH THE WESTERN END OF THE SWELL REGION WHICH WILL BRING A SIMILAR
NORTHERLY REINFORCEMENT FOR SATURDAY.

WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA
THROUGH THE WEEKEND AND INTO NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
POWELL









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